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Photo © Keith Williams
Photo © J. C. Lucier

Bees Buzz, Birds Bail

In temperate forests, birds and bees both use tree cavities for their nesting activities. Because bumblebees prefer cavities filled with plant materials for insulation, they may benefit from stealing freshly built bird nests. A recent study from Seoul National University in South Korea showed that the buzz of a bumblebee in a nest might be one of the ways it scares off the birds.

The researchers observed that bumblebees were detected in up to 21% of freshly built nests of tits (relatives of our chickadees) and were not detected in nest boxes without any bird nests. Using miniature speakers and bumblebee mounts, researchers demonstrated that when birds heard the buzzing sound in their nest box, they became distressed and often left the nest. It is therefore possible that a bumblebee could use its buzz as a warning signal to oust birds from their newly-built nests.

Bees are important pollinators of the foods that birds and people need to survive, and they are also prey for birds, so sharing nests with them is not all bad. If you’d rather not have bees buzzing in your nest boxes, you can minimize the likelihood of bees colonizing your boxes by keeping them plugged until just before the breeding season of the target species. If bees have already moved into your box, consider leaving them “bee” and putting up an additional box for the birds. Like bird nests, bumblebee nests are temporary and can be cleaned out once the bees are finished. Don’t spray pesticides into a nest box, as the residue may remain even after cleaning and harm future nestlings.

There is so much to learn about the natural world, even about non-feathered friends, simply by observing birds’ nests! As a member of the world’s largest team of nest monitors, you can be a part of the buzz. Help us grow our hive of data by telling your friends about NestWatch.

Cornell Lab of Ornithology

Cornell Lab of Ornithology